The Probability-Impact (P-I) risk matrix is one of the frequently used techniques among the qualitative risk assessment methods in construction projects, which usually utilizes a 1 to 5 rating scale in order to quantify risk. Decision-makers usually apply their personal judgement, experience, and intuition for the quantification of the intensity of a probable risk event in the first stages of analyzing risks. However, the fluctuation observed by many researchers in the risk rating scales that differs from one individual to another is a substantial drawback of the qualitative risk assessment process where some driven factors may have influence the ratings. Hence, in this research the effects of two factors such as decision-makers’ attitudes towards a potential risk event and their assumptions about its controllability during the qualitative risk assessment process in international construction projects are studied through a questionnaire survey. In this survey, 74 professionals and 7 academics from the Turkish construction industry have participated. Two hypotheses are tested for their validity, confirming that risk attitude and assumption about risk controllability are the two critical factors that may have influence on the the risk ratings of the individual decision-makers.